From 1fc08f5e9ef733ef1ce6f363fecedc2260e78974 Mon Sep 17 00:00:00 2001 From: dim Date: Sat, 14 Apr 2012 13:54:10 +0000 Subject: Vendor import of llvm trunk r154661: http://llvm.org/svn/llvm-project/llvm/trunk@r154661 --- lib/Support/BlockFrequency.cpp | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) (limited to 'lib/Support/BlockFrequency.cpp') diff --git a/lib/Support/BlockFrequency.cpp b/lib/Support/BlockFrequency.cpp index a63bf83..84a993e 100644 --- a/lib/Support/BlockFrequency.cpp +++ b/lib/Support/BlockFrequency.cpp @@ -70,8 +70,13 @@ BlockFrequency &BlockFrequency::operator*=(const BranchProbability &Prob) { assert(n <= d && "Probability must be less or equal to 1."); - // If we can overflow use 96-bit operations. - if (n > 0 && Frequency > UINT64_MAX / n) { + // Calculate Frequency * n. + uint64_t mulLo = (Frequency & UINT32_MAX) * n; + uint64_t mulHi = (Frequency >> 32) * n; + uint64_t mulRes = (mulHi << 32) + mulLo; + + // If there was overflow use 96-bit operations. + if (mulHi > UINT32_MAX || mulRes < mulLo) { // 96-bit value represented as W[1]:W[0]. uint64_t W[2]; @@ -82,8 +87,7 @@ BlockFrequency &BlockFrequency::operator*=(const BranchProbability &Prob) { return *this; } - Frequency *= n; - Frequency /= d; + Frequency = mulRes / d; return *this; } -- cgit v1.1